Most organizations have a storage system that includes one or more disks or disk arrays for storing file systems for the organization, and one or more file servers which control accesses to the disks. For example, in a Storage Attached Network (SAN) system, external file servers communicate with one or more disk arrays using a Fibre Channel block protocol.
Network Attached Storage (NAS) systems provide an integrated file servers/disk array solution which may be accessed via a traditional Internet Protocol (IP) network, usually via a Local Area Network (LAN) such as the Ethernet. External hosts, referred to as NAS clients, use file server protocols such as Common Internet File System (CIFS) and Network File System (NFS) to communicate with NAS systems. NAS systems typically comprise a ‘front end’ that includes one or more file servers and a ‘back end’ that includes multiple disk arrays to provide single site redundancy. Because NAS systems provide an integrated file server/disk array solution that may be easily attached to an existing IP network, file server capacity may easily be increased by adding additional NAS systems, or adding additional file server and/or disk array components to a NAS system as businesses grow.
Often the reliability of the NAS system is a key factor in the ability of the organizations to service customers. Thus it is critical that many organizations, such as financial institutions and the like include backup and recovery mechanisms that allow the NAS to quickly recover from faults and disasters and to continue operation without loss of client data. Disaster Recovery (DR) is a term that refers to the ability to recover from the loss of a complete site, whether due to natural disaster or malicious intent. Disaster recovery strategies include storing copies of data at both primary and backup sites through data mirroring, as well as providing standby data management components at backup sites. In the event of a disaster at the primary NAS, the copy of the production file system stored in backup storage as well as standby data management components may be used to support client applications until the primary NAS is restored. Replicating NAS systems in this manner allows business continuity to be achieved during disasters and other failures.
In order for disaster recovery to be successful, it must be ensured that the backup NAS has at least the same capabilities (including but not limited to number and type of network connections, file system access capabilities to enable business continuity, etc). as the primary NAS; a backup NAS that is unable to provide the features and perform the functions of the primary NAS will not allow full recovery in the event of a disaster. Constructing a NAS capable of disaster recovery involves building a backup (secondary) NAS that has all the capabilities of the primary NAS and failing over components of the primary NAS to mirrored and standby components of the secondary NAS as needed.
Current methods of initializing primary and secondary NAS relationships for disaster recovery lack coordination; typically network administrators at each site perform manual mappings using scripts that are tailored to the particular architecture of each NAS. The primary and secondary NAS are typically geographically remote, and communication between the network administrators regarding the available resources and particular system requirements may be difficult and lack crucial detail. As the types and versions of NAS components continue to grow, it can often be difficult for network administrators to comprehend the capabilities and requirements of the NAS. As a result, components of a primary NAS may be erroneously mapped to components in a backup NAS that do not support its feature set. Such incompatible mappings result are often not evident until disaster recovery is attempted, at which time it may be too late to salvage all file system data. It would be desirable to identify a method and apparatus that would allow a disaster recovery system to be built with accuracy